4. Draw lines between the marks. And make another mark 5mm from the first. Repeat step 2-4 on the other side too. 5. Now you want to make a template of how you want the two loose sideparts of the box to look like. I wanted mine to look like this.

6. If you made the template in step 5 equal on both sides you can skip this step and do step 7, to see where you should draw around the template. But if you, like me, made the sides different you want to make sure that they look similar when you fold the box together. Start by drawing around the template on the same places as I did in the picture below. Notice that I turned it.